The present invention relates to a structure for securing a weight to a metallic hollow golf club head and more particularly to a metallic hollow golf club head in which a weight formed from a different type of metal to a sole plate on the main body of the club head formed from titanium or titanium alloy can be firmly secured thereto.
In recent years, a hollow golf club head consisting of the light metal titanium or titanium alloy has attracted considerable attention due to its superior driving distance capacity. Since this hollow golf club head is made from light metal, a weight consisting of metal having a large specific gravity is secured to the inner surface of the sole plate in order to lower the center of gravity and increase the moment of inertia.
Generally, however, it is difficult to weld together metals of different types, and especially difficult when one of the metals is titanium or a titanium alloy. Consequently, when the sole plate and the weight consist of metals of different types such as in the above-mentioned hollow golf club head, there has been a problem of insufficient strength in the welded joint.
A conventional countermeasure against this problem was disclosed in Japanese patent application Kokai publication No. 6-296716 which proposed a method of securing a weight to the sole plate using a screw. However, this type of securing method has the disadvantage that when the head is used as a golf club head, vibration resulting from striking the ball or making contact with the ground produces unpleasant sounds and causes looseness.
Alternatively, as shown in FIG. 15, a securing method has been proposed wherein the weight 4 is fitted to the sole plate 2 by means of a dovetail groove. However, this method has the disadvantage that the high-precision manufacturing processing required is time-consuming and increases costs.